The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Powertrain architectures comprise torque-generative devices, including internal combustion engines and electric machines, which transmit torque through a transmission device to an output. One exemplary transmission is a two-mode, compound-split, electro-mechanical transmission which utilizes an input member for receiving motive torque from a prime mover power source, for example an internal combustion engine, and an output member for delivering motive torque from the transmission to a vehicle driveline. Electric machines, operable as motors or generators, generate a torque input to the transmission, independently of a torque input from the internal combustion engine. The electric machines may transform vehicle kinetic energy, transmitted through the vehicle driveline, to electrical energy potential that is storable in the electrical energy storage device. A control system monitors various inputs from the vehicle and the operator and provides operational control of the powertrain system, including controlling transmission operating state and gear shifting, controlling the torque-generative devices, and regulating the electrical power interchange between the electrical energy storage device and the electric machines.
During operation of the electric machines, heat is generated in the various electric power devices, including the electric machines, power inverters, and electrical energy storage devices, e.g., high voltage batteries. Heat transfer devices, including heat sinks, heat exchangers, and cooling systems may be incorporated to manage waste heat in the system. Systems include closed-circuit cooling systems which flow liquid coolant over heat sinks and pump the coolant through a heat exchanger to remove the waste heat. Other systems include fan devices which pass air over the heat sink devices to remove heat therefrom.